Suction-lipectomy, otherwise known as liposuction, is a common surgical procedure used to aesthetically improve the shape of the human form, and is one of the most common body-enhancing procedures performed today. During liposuction, small incisions are made in the area where the procedure is to be performed and a cannula is inserted into the fatty deposits below the skin. The cannula breaks through the fibrous sacks containing the fatty fluids, and said fluids are then suctioned out of the body and through the cannula by means of a vacuum applied to the cannula.
There are currently two distinct methods by which surgeons perform a liposuction procedure. Each requires the surgeon to repeatedly push and pull the cannula to break through the fatty deposits so that the fatty liquids may be suctioned away. The first of the methods is called the "tunneling" procedure, and involves the surgeon making one or two incisions into the fatty tissue of the patient. The cannula is then used to make radial excursions ("tunnels") into the fatty deposits surrounding the incisions. At the area of each of these excursions the fatty liquids are suctioned away by the vacuum applied to the cannula. In the second, original, method of liposuction, an entire layer of deep fat is removed from beneath the skin, which is hopefully naturally followed by skin retraction.
Each of the techniques described above requires the surgeon to manually push and pull, back and forth, the cannula while making the normal twenty to thirty tunnels that are required to remove the necessary amount of fatty tissue. As can be expected, the constant, repeated, pushing and pulling of the cannula by the surgeon is extremely tiring for the surgeon, and limits the duration during which the surgeon can perform liposuction procedures at his optimal performance level. In addition, the procedure is extremely traumatic for the patient, and the patient's skin will typically turn black-and-blue in the affected area for up to several weeks after the procedure. It has been found that the use of a smaller cannula is less traumatic for the patient. The use of a smaller cannula, however, results in greater fatigue for the surgeon, as he is required to make more tunnels to remove the same amount of fatty deposits as would be required with a larger cannula.
To remedy the preceding problems, several different powered liposuction devices have been proposed. U.S. Pat. No. 5,352,194 to Greco et al. provides for a pneumatically driven powered cannula which is controlled by either mechanical abutment means or a series of switches that can be turned on or off to control the stroke length of the cannula. In addition, it is proposed that the cannula be controlled by the modulation of a servo valve, such as by an electronic signal generator or a wave form generator.
U.S. Pat. Nos. 5,348,535 and 5,643,198 to Cucin disclose a cannula assembly that includes an inner and an outer cannula, with each having an aspiration aperture at the distal end such that they are in at least partial registration to form an effective aspiration aperture. During a liposuction procedure, one of the cannulas reciprocates while the other is stationary relative to the housing. The reciprocation of the cannula is achieved by means of either a gas driven piston-type motor, the travel of which is manually controlled by moving a sliding member extending from the hand-holdable housing, or by manually adjusting by hand the amount of gas driving the piston-type motor.
Various problems exist, however, with these prior liposuction devices. In particular, it is difficult to regulate the stroke length and rate of the cannula, as the surgeon must interrupt the procedure each time he wishes to adjust the reciprocation of the cannula. In addition, in neither of the above devices is the stroke length of the cannula tied to the stroke rate, such that the greater the length of the stroke the slower the stroke rate. Tying the stroke length of the cannula to the stroke rate provides greater safety for the patient, especially when performing liposuction procedures in particularly sensitive areas of the body such as the face and neck, and also provides greater ease of use for the surgeon. Furthermore, none of the prior cannulas allow for the easy sterilization of the entire hand-holdable handle assembly and cannula.
Accordingly, it is the object of the present invention to provide a power-assisted liposuction device to assist the surgeon in performing liposuction procedures with greater control and less fatigue.
It is correspondingly an object of the present invention to provide a power-assisted liposuction device to enhance the safety of the patient, both through easing the fatigue of the surgeon, and connecting the stroke length of the cannula to the stroke rate such that the longer the stroke length of the cannula the slower its stroke rate.
It is a further object of the present invention to provide for a power-assisted liposuction device in which the cannula reciprocates relative to the hand-holdable handle assembly by means of a piston rod driven by compressed gas.
It is still a further object of the present invention to allow the stroke length and correspondingly the stroke rate to be easily adjustable, and for the adjustment to be able to be made without the surgeon needing to interrupt the liposuction procedure.
It is another object of the present invention to construct the power assisted liposuction device such that any part of said device that must be sterilized, including the cannula, its connection to the hand-holdable handle assembly, and the hand-holdable handle assembly itself are able to be easily sterilized, and can be sterilized without the need to disassemble the entire said device.
An even further object of the present invention is to attach the cannula to the hand-holdable handle assembly by means that allow for the easy and quick changing of cannulas during a liposuction procedure or for purposes of sterilization.
These and other objects and uses of the present invention will become apparent upon consideration of the description that follows.